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## How Heavy Is a Petabyte?495

Jon Morgan writes "Whilst heaving around numerous data storage systems to sell (they weigh A LOT!), we got to wondering: How heavy is a Petabyte of data storage? Our best guess is 365KG, which is 6 million times lighter than in 1980! But is there a lighter way to store a Petabyte?"
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## How Heavy Is a Petabyte?

• #### library of congress (Score:5, Funny)

on Wednesday July 08, 2009 @06:23PM (#28629249)

How heavy is a Library of Congress?

• #### Re:library of congress (Score:5, Informative)

on Wednesday July 08, 2009 @06:41PM (#28629439)
According the Library of Congress' website they have approximately 32 million books. A bit of googling turned up that an average book weight about 12 ounces. So, 32 million * 12 ounces = 10,886,216.9 kilograms
• #### Re:library of congress (Score:5, Insightful)

on Wednesday July 08, 2009 @06:59PM (#28629621)

See, this is why I love slashdot. Ask a silly question and more often than not you'll get an answer.

• #### Re:library of congress (Score:5, Funny)

on Wednesday July 08, 2009 @07:56PM (#28630195)

See, this is why I love slashdot. Ask a silly question and more often than not you'll get an answer.

And it's usually, "fuck off" ;)

• #### Re:library of congress (Score:4, Funny)

on Wednesday July 08, 2009 @07:06PM (#28629689) Journal

according to some website [techtarget.com] the LOC holds aprox. 10 terabytes worth of information.

which means that 102.4 LOC's would equal 1 petabyte.

10,886,216.9 * 102.4 = 1,114,748,610 kg

or aprox 2,457,600,000 lbs.

• #### Re:library of congress (Score:5, Insightful)

on Wednesday July 08, 2009 @09:58PM (#28631273) Homepage
That's about half of what 1 terabyte of magnetic storage weighed in 1980, so I guess that in 1980 books still had better information density than magnetic media.
• #### Re:library of congress (Score:5, Funny)

on Wednesday July 08, 2009 @07:29PM (#28629907) Journal

If we take a book to have approximately 7000 BTU per pound when incinerated (newsprint is about 7,500) then we get 437.5 BTU per ounce.

So 1 LoC = 14,000,000,000 BTU or 14,770 gigajoules.

Finally! A heat unit LoC equivalent!
=Smidge=

• #### Re: (Score:3, Informative)

unfortunately, the practicality of removing the BTU from a book is more effort than it's worth? Have you ever tried to burn a book? It's actually not as trivial as one would think.
• #### Re:library of congress (Score:4, Interesting)

by Anonymous Coward on Wednesday July 08, 2009 @07:36PM (#28629963)

10,886,216.9 kilograms or 10.9 kilotons is slightly less than one Hiroshima.

So if every book in the Library Of Congress was made of TNT and you detonated them all together, the total yield would be slightly less than one very small atomic bomb. Fuck.

• #### A lot heavier than... (Score:5, Interesting)

on Wednesday July 08, 2009 @06:47PM (#28629495) Journal

and a lot bulkier than...

a few strands of DNA.

• #### Re:A lot heavier than... (Score:4, Informative)

on Wednesday July 08, 2009 @11:56PM (#28632189)

Well, a rough check shows that each base pair (and backbone) weighs about 614amu, which gives a weight of 10^-21 grams for 2 bits. So, pure DNA weighs about a 4ug per petabyte, supposing my calculations are correct.

However, that's hardly fair. The density of bits is _far_ from the density of the actual storage. After all, a hard disk uses only extremely small regions (probably only a few million amu) on the surface of a disk. However, the motors, the case, and even the disk (substrate) itself are orders of magnitude heavier than the bits themselves. I'd be rather surprised if the actual storage was much more than a couple grams.

The point is, of course, that there are all kinds of ways to store data, but when it comes down to weight, the control mechanisms are what matters. For this reason it's extremely unlikely that DNA will _ever_ be used as storage, except if we start making bio-computers.

Also, for what it's worth, the human genome only stores about 770MB, only a bit more than a CD.

• #### Re:library of congress (Score:4, Interesting)

on Wednesday July 08, 2009 @06:57PM (#28629609)
Asking a question like this is about as silly as asking how wide a year is. It's just not immediately obvious that this question makes no sense because it gets confused with the similar question 'what is the lightest device(s) capable of storing a petabyte of information.
• #### Re:library of congress (Score:5, Insightful)

on Wednesday July 08, 2009 @07:10PM (#28629733) Journal
A year is two AU wide, about 300 million km.
• #### Re: (Score:2)

somebody hurry up and mod this guy insightful
• #### Re: (Score:3, Interesting)

No, that's diameter of the earth's orbit around the sun. A year would be the circumference which is 940 million kilometers.
• #### Re:library of congress (Score:5, Insightful)

on Wednesday July 08, 2009 @07:38PM (#28629977) Homepage

So when some asks you "How wide is this circle?" do you tell them the circumference? If someone asks you, "How wide is this desk?" do you provide them the length of the perimeter?

I propose that your definition makes less sense than any of this. :)

• #### Re: (Score:3, Interesting)

In my head I equated orbit length to "width of the year" since I was thinking of a timeline, and a timeline has width (from 1st Jan to Dec 31st) and at each point on the timeline the earth is at a certain point on its orbit which corresponds to a distance from its initial position.
• #### Re:library of congress (Score:4, Insightful)

by Anonymous Coward on Wednesday July 08, 2009 @07:42PM (#28630013)

A year is actually 0AU wide, 6 months would be 2AU

• #### Re: (Score:3, Insightful)

Well, we can convert distances into time intervals via relativity...

To nobody's surprise, the conversion factor is a well known physics constant. c.

So a year is exactly one light-year wide.

• #### Re: (Score:2)

7

Filter error: You can type more than that for your comment.

• #### Need conversion to units of Libraries of Congress (Score:5, Funny)

on Wednesday July 08, 2009 @06:23PM (#28629253)
What are these Petabytes of which you speak? America measures data in units of Libraries of Congress.
• #### Re: (Score:2, Informative)

I've seen stats that all the books ever written by mankind add up to 50 PB of data storage. Presumable unZipped :)
• #### Re: (Score:3, Informative)

I've seen stats that all the books ever written by mankind add up to 50 PB of data storage. Presumable unZipped :)

You've seen ESTIMATES.

• #### Re:Need conversion to units of Libraries of Congre (Score:3, Informative)

51.2 LoC's

Assuming LoC is still = 20TB

• #### MicroSD (Score:5, Informative)

on Wednesday July 08, 2009 @06:23PM (#28629255)
...weighs something like 300mg/card. That's 48GB/gram, or a bit over 20g/TB, or 20Kg/PB.
• #### or 2.5" drives? (Score:3, Interesting)

I think that a 2.5 inch drive weighs less than half the weight of a 3.5 inch drive, so using twice as many of the 2.5" drives (available up to 1TB today) will reduce the weight.
• #### Re:or 2.5" drives? (Score:4, Informative)

<kevinforge@nosPaM.gmail.com> on Wednesday July 08, 2009 @06:57PM (#28629603) Homepage Journal
Problem is those methods of dropping the weight, also increase the cost (TFA assesses both).

My problem with the assessment however, becomes even more glaringly obvious when you look at the micro SD proposal in the grandparent. If you are going to have a single SD card reader and plug these cards in as needed, the weight estimate is ok. If however all 1 PB of data must be immediately available to your software, the weight gos up dramatically.

In the case of 3.5" SATA HDDs, that weight/cost should include a storage system that renders all the data available at the same time. 140 Lbs for 48 Hard drives is reasonable. [sun.com]

Depending on your RAID Level, 1,500 Lbs per petabyte is closer to reality. 1,700 Lbs to 2,000 Lbs per petabyte if you add the rack to the equation.

BTW: Doing something sane, like RAID, instead of JBOD or RAID 0, will increase that mass somewhat.
• #### Re: (Score:3, Insightful)

But the smaller the chipsets, the larger - relatively - the packaging becomes. You can't just keep shrinking down the packaging, after all.. it would get far too flimsy.
So what you'd really need to weigh is the actual PCB with components, but sans all but a sliver of the bit that is the connector (the copper strips etched into the PCB to function as such).

• #### Re: (Score:2)

Yeah, something solid-state, definitely. I was thinking SDHC 32GB cards... but those work out to a little under 64g/TB, so microSD is a lot lighter. You could even throw in one microSD-to-SD adapter and still be lighter. ;)

• #### Re:MicroSD (Score:5, Interesting)

on Wednesday July 08, 2009 @07:27PM (#28629895) Homepage

Technically, if you don't count the hardware to read the data, we could simply remove the hard disk platters from the drive. Since most of the drive's weight is made up of the casing and read electronics, it would probably swing the data/weight ratio back in the favor of hard disks.

• #### About the weight of a floppy (Score:2)

LINE 10 PRINT "byte"

LINE 20 goto 10 REPEAT 8.881784197E-16

Then you wait for long time.....
• #### Re: (Score:2)

The number of bits in a petabyte: 9*10^15. Age of the universe in seconds: 4*10^18. So, a room with 480 of these servers could hold that much data. My entire life, I've used the age of the universe in seconds as a number so huge, that we could just assume nothing would ever approach it.

The meaning of life: you contribute on the order of 1 bit towards the evolution of the human genome. Kinda makes me feel small.

• #### Re: (Score:2)

Of course something approaches it, and surpasses it..
try micro seconds. That's, like, 1000 times more then the seconds in the universe~

Seriusly, if you captured all the data you experice throught your life, it would blow though several Petabytes of storage. Probably in a day.

• #### There is a way! (Score:3, Insightful)

on Wednesday July 08, 2009 @06:30PM (#28629319)

It will take me a while but committing all that data to my memory won't add any measurable weight to me at all.

• #### Re: (Score:3, Funny)

Right, but to answer the question, we still need to know your weight!

• #### Re:There is a way! (Score:5, Informative)

on Wednesday July 08, 2009 @07:25PM (#28629873)

Insightful? Assuming you can perfectly remember 1 byte per second, you'd be memorizing for over 100 million years. The human brain is great and all that, but no way are you going to store that much data while being able to reproduce it later.

• #### Re:There is a way! (Score:4, Interesting)

on Wednesday July 08, 2009 @09:05PM (#28630873)

Insightful? Assuming you can perfectly remember 1 byte per second, you'd be memorizing for over 100 million years. The human brain is great and all that, but no way are you going to store that much data while being able to reproduce it later.

Considering a single "frame" of vision for a pair of human eyes is estimated at 576 megapixels (truncating at peripheral vision). We'll imagine that each pixel is assigned a 16-bit hexadecimal value. That means, each time you glance at something, each frame would be calculated at a little more than 1/1000th of a terabyte. The lowball framerate for the human eye is about 18 frames/second (things look fluid). That means that every 50 seconds, your eye is downloading a terabyte of information. He'll absorb it in less than a day through eyesight alone. That doesn't include audio, olfactory, touch, or taste. His brain's data compression will downsize a lot of that information, so it will take him more than a day, but for your i/o ports, taking in a petabyte of information is a daily task.

You'd be hard-pressed to find a living organism that downloads information at 1B/sec

• #### Re: (Score:3, Funny)

I think there was a movie about this type of thing.... But I don't remember what it was called...

Johnny something-or-other....
• #### Re: (Score:3, Interesting)

Pointless. You could put 1 billion people on a scale and have them all memorize data as fast as they could and the weight won't change (correcting for evaporation, etc.).

-b

• #### Cloud computing (Score:5, Funny)

on Wednesday July 08, 2009 @06:30PM (#28629321)

Just stick the petabyte on the cloud! Clouds are as light as air!

(why yes, I am from Marketing, why do you ask?)

• #### Re:Cloud computing-Clouds in Elephant Units (Score:5, Informative)

on Wednesday July 08, 2009 @06:52PM (#28629547)

Clouds are as light as air!

A common misconception, and just saying it on Slashdot doesn't make it true. Clouds weigh more than elephants - much more. In fact, you can learn the weight of clouds in elephant units here. [wsi.com]

Not only that, but clouds are usually darker than the air around them.

• #### Re: (Score:2)

For such a small article, that was a fascinating read. Thanks for the link.

• #### Re:Cloud computing-Clouds in Elephant Units (Score:4, Informative)

on Wednesday July 08, 2009 @07:01PM (#28629647)

Air also weights more than elephants.
In fact, every square meter of the world has 2 elephants of air on top of them.

So "missconception" my ass.

• #### Re:Cloud computing-Clouds in Elephant Units (Score:4, Funny)

on Wednesday July 08, 2009 @08:39PM (#28630649)

In fact, every square meter of the world has 2 elephants of air on top of them.

Tell that to my doctor the next time I stand on his scales.

• #### Re:Cloud computing-Clouds in Elephant Units (Score:5, Funny)

on Wednesday July 08, 2009 @09:35PM (#28631109)
and all of this sits upon a tortoise? Amazing!
• #### Re:Cloud computing-Clouds in Elephant Units (Score:5, Funny)

on Thursday July 09, 2009 @02:18AM (#28632909) Homepage Journal

No, not just one. It's tortoises all the way down, young man.

• #### Re: (Score:3, Insightful)

Being pedantic is the wrong place to fail , like you did.

You failed to take the weight of air into account. Why, when you do that they are, in fact, lighter then air.
Otherwise they would fall down, and we call that 'rain'

• #### Re: (Score:3, Interesting)

Thanks for nothing Peggy LeMone. Saying that a "typical cumulus cloud" weighs as much as 100 elephants is a meaningless statement without giving us a hint as to what the hell is the size of a "typical cumulus cloud". I bet we are talking about a hell of a lot greater volume than 100 elephants.

Here is an equally interesting piece of news for you: a pile of feathers is heavier than a tank! Of course it all depends on the size of the pile but who can bother with those little details.
• #### Re: (Score:3, Informative)

Here's the one that'll really get you:

A pound of feathers weighs more than a pound of gold.

• #### Re: (Score:3, Informative)

That is, of course, due to the fact that a Troy pound (used for gold) measures a lower weight than an avoirdupois pound.
• #### lim-0 (Score:3, Insightful)

on Wednesday July 08, 2009 @06:31PM (#28629333)
Since data storage is just one case of transmission channel (just sending it through time, not space) you can store the 6 Petabytes in a transmission. All you need to do is place one sender here, and one eh, let's say at the end of the Universe. As long as the data is being transmitted, it doesn't really weight anything. Yes silly question will get a silly answer :)
• #### Hell - terabytes were huge just 10 years ago (Score:2)

I remember going to NAB in 1997 and some company had a terabyte system the size of a double door SubZero Fridge. [condodomain.com] I thought a terabyte would be an unimaginable amount of space, then. Now I have 1.8TB of drives on my desk, and 4 TB at my office...

RS

• #### but-electrons-don't-weigh-anything (Score:3, Interesting)

on Wednesday July 08, 2009 @06:33PM (#28629357) Homepage

Whatever gave you that idea?

• #### Re: (Score:2)

Electron [wikipedia.org]

Mass:
9.10938215(45)x10-31 kg
5.4857990943(23)x10-4 u
[1822.88850204(77)]-1 u
0.510998910(13) MeV/c2

Regardless of what that shit means in tangible terms, it at least means they weigh something, as far as we like to think anyways.

• #### About 2 Kilos (Score:5, Interesting)

on Wednesday July 08, 2009 @06:33PM (#28629359)
Nobody knows exactly how much data the average human brain can hold, but one estimate [geocities.com] is 500 to 1000 TB. If the average adult human brain weighs about 1.3 or 1.4 Kilos [washington.edu], then "about 2 Kilos" would hold 1 Petabyte.
• #### Re: (Score:2)

Is that normal brains or shrub brains [dailymail.co.uk]?

• #### Re: (Score:2)

I'm no expert in this field but I think the link that you provided had underestimated the human brain by many orders of magnitude. The human brain is not a hard drive. I don't think there is even any counterpart to it in current computer technology (maybe quantum computing?), whatever that is, so the comparison is meaningless. The brain doesn't just "store" information like a hard drive. It analyses, modifies, categorises, correlates, extrapolates, fills in missing blanks, filters and blanks out others and
• #### Re:About 2 Kilos (Score:4, Insightful)

on Wednesday July 08, 2009 @07:44PM (#28630027)

I'm no expert in this field but I think the link that you provided had underestimated the human brain by many orders of magnitude. The human brain is not a hard drive. I don't think there is even any counterpart to it in current computer technology (maybe quantum computing?), whatever that is, so the comparison is meaningless. The brain doesn't just "store" information like a hard drive. It analyses, modifies, categorises, correlates, extrapolates, fills in missing blanks, filters and blanks out others and many other things that we are just beginning to discover. For example, a human child will quickly grasp the concept of doors and doorknobs, without any "programming" (I've had toddlers so believe me on this). This is why I think A.I. enthusiasts will ultimately fail.

People like you drive me nutters. The human brain has billions of years of evolutionary programming built into the seperate layers of the brain, there are so many built in functions that we don't even realize it in normal everyday activities. For example, your brain is "hardwired" from birth to recognize human faces, and to emit "happy juice" when the faces are familar or matched with motherly smells. Just because its not programmed after birth, does not mean that the hardware itself is not built for the task. This is no different from creating a custom asic or fpga for doing GA's or ANN's.

• #### Theoretically quite close to zero ... (Score:2)

... if you transmit it into space encoded in waves of light. Of course, you have to travel faster than light to get ahead of the signal and read it again ...

• #### Re:Theoretically quite close to zero ... (Score:5, Funny)

on Wednesday July 08, 2009 @06:46PM (#28629483)

Or you could just stick a mirror "out there". The light would quite conveniently come back at you. Or you could sneak around the other side of the universe and wait for the light...

• #### Re: (Score:2)

There was a way discussed on Slashdot a while back on how to slow light to around 30 miles per hour.

• #### Re: (Score:2)

I can't remember clearly, but did that way involve curved fiberoptic cabling?

• #### Re: (Score:2)

Or you could tie the hard drives to a blimp. The mass is still there, but the weight is zero.

• #### "But is there a lighter way to store a Petabyte?" (Score:5, Funny)

on Wednesday July 08, 2009 @06:35PM (#28629385) Homepage

Sure. Store it in a WOM chip. They only weigh a few grams, hold literally unlimited data, and are really fast.

• #### Minimum mass of a Petabyte (Score:4, Interesting)

on Wednesday July 08, 2009 @06:36PM (#28629393) Homepage

Thinking about the decrease in mass of a petabyte got me thinking about Information Theory and the minimum energy required to store a bit. Or rather, to irreversibly manipulate one bit of information, which I think describes the act of writing to any kind of RAM (disk or otherwise). If I extrapolate that to also mean a mass whose rest energy is sufficient to manipulate a bit, that could give the theoretical minimum mass for a bit of storage. I don't actually know enough information theory to know that value, or even if the comparison from energy of information manipulation to mass of storage is valid, but it struck me as interesting and maybe somebody knows? What's the minimum mass of a petabyte?

• #### Re:Minimum mass of a Petabyte (Score:5, Informative)

on Wednesday July 08, 2009 @07:26PM (#28629881)

That was my dissertation topic, conventional systems require ~kT per bit (k is the Boltzmann constant = 1.3806503 Ã-- 10-23 m2 kg s-2 K-1 and T is the temperature of the gate in Kelvin) for each read. Quantum systems can access well below that by various trickery (single photon optical computers can reduce this by a thousandfold). In theory a individual photon can hold huge amounts of data in it's state vector before collapse. The trick is making a measurement on enough of these photons to extract the info you need while overcoming shot noise.

• #### It depends.. (Score:4, Funny)

on Wednesday July 08, 2009 @06:43PM (#28629469)
Are you storing mostly 1s or mostly 0s? Everybody knows they don't weigh the same.
• #### Re:It depends.. (Score:5, Funny)

on Wednesday July 08, 2009 @06:46PM (#28629489)
Here's an interesting discussion [microsoft.com] on the topic ;)
• #### Tapes? (Score:2)

What about TB tapes? I assume those would still weigh less than their Hard drive equivalents. For that matter, what about high density optical media? Does a 2TB Hard drive still weigh less than 40 Blu-Rays? I have no idea, but I'm guessing tap at least might still weigh less.

• #### Compression (Score:2)

Assuming you're not already compressing your data, this would be a good method to make it "lighter." A quick Google search has a test which shows gzip compressing things down to between 25% to 40% of their original size. This pretty much makes the data useless for mining or quick lookups, but it would drop the weight of storage media required, regardless of what you're using to store it. If it's just data that needs to be stored as a backup then it shouldn't be too much of a problem.

Some other poster did

on Wednesday July 08, 2009 @06:54PM (#28629569)
This subject has already been discussed [microsoft.com].
• #### Try using Micro SD cards instead (Score:5, Insightful)

on Wednesday July 08, 2009 @06:57PM (#28629601)
With 32gb cards weighting 0.5 grams one terabyte should require 32 cards, or 16 grams. 1024 terabytes should then weight 16384 grams, or a bit more than 16kg.

I don't think there is a storage media with higher density available commercially right now - and probably not until the 64GB microsd cards becomes available.

• #### A bit lighter I would think (Score:2)

You can buy a 16GB microSDHC which weighs 0.05oz (1.4g). You would need 62,500 of them to make a petabyte. That comes to a total of just 87.5kg. Of course this does not include the interface needed to access them.
• #### And her I thought a petabyte was... (Score:2)

what you call it when you pet your pet and they byte you.

• #### What kind of shop do you work for ... (Score:2)

where you sit around dealing with heavy petting all day? And don't you just think that a lighter version of it would just be annoying? Maybe even leading to the infamous BBOD? Or maybe I am just reading this wrong ...
• #### temperature (Score:2)

Doesn't that depend on the temparature?

Stephan

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